Hi
Welcome to the forum. I have been around for quite some time and I can tell you first hand that this is THE place to come for each and every reason. Whether it to be to seek info, to discuss notes and questions or to share your joy or grief about your score,interview calls and acceptances and rejections.
You HAVE to have to have Dental Decks and Past papers. The 2006 version has just come out and you may want to get that. The 2004 version and 2001 version have helped a lot of members here score very well on the part I.
The papers, I believe, are not as helpful as they were some time back but they are still a very good guideline to have.
You may want to refer to other materials like Kaplan,USMLE books, test books etc.
You can take the test as a written one in July and December and on the computer at just about any time in the year. There are quite a few schools offering the Advanced Standing Program and the best way is to really check the website of each and ever school.
I hope this helps.